Losing candidates are nearly always blamed for their losses. If they aren't, a wave is. I'm going to look over the 2006, 2008, and 2010 elections and explore who was to blame for each.
First, let's go over some things about waves.
1) Open seats are always the first to go: This is a corollary to the incumbent advantage that any political scientist knows exists to some extent, even in "anti-incumbent" years.
2) Some driftwood is always washed ashore: Driftwood doesn't always mean an unintelligent or extremist candidate. Kristi Noem and Joe Courtney, both very able legislators, were washed ashore with their waves. Driftwood candidates can sometimes stay in the House for years due to redistricting, district trends, or incumbency.
3) Waves affect the House, Senate, and Governors' offices.
4) Special elections aren't affected by waves. In 2010, Democrats won PA-12 in a special but lost the much bluer HI-1, which they'd pick up a few months later. Janice Hahn and Kathy Hochul won open seats by similar margins in specials this year. Special elections are, as DCCyclone (I believe) put it, simply special.
5) Waves can affect recruitment. The fact that a wave will occur can lead stronger candidates rather than sacrificial lambs to declare for the race. This effect can then continue to multiply.
Let's start with the 2006 Dem. wave.
In 2006, Democrats won 54.23 of the 2-party vote. Since the end of (most) conservaDems around 1994, the % above or below 50 that either party got is a good way to show the size of the wave.
2008: D+5.56
2006: D+4.23
1996: D+0.16
2000: R+0.16
1998: R+0.47
2004: R+1.36
2002: R+2.43
1994: R+3.53
2010: R+3.53
I then add one percent to whatever the Democrats get due to the fact that Democrats are more clustered into urban districts which give them a higher percentage of the vote. From this, we can see which seats would've switched hands in a neutral year.
Open Seats:
AZ-8: Very conservative Randy Graf stood no chance against a Blue Dog in a wave year. Gabby Giffords had this in the bag, barring a large screw up, before her campaign even started. Thus is the nature of wave years.
CO-7: Another western, swingy seat where the Republican had no chance due to the wave.
IA-1: I'm not sure if Jim Nussle would've held this anyway due to his conservatism, but with his retirement, Braley's victory was a given.
NY-24: I'd forgotten Mike Arcuri even existed. However, he had a healthy victory in another swingy seat in a wave year.
OH-18: Anyone from the opposite party as Bob Ney was a good choice here, so Zack Space cruised.
TX-22: Anyone from the opposite party as Tom DeLay was a good choice here, so Nick Lampson cruised.
Incumbent Losses:
CT-5: The question is, do we blame this on the incumbent (Nancy Johnson of the EXTREMELY negative ads) or the challenger (Chris Murphy, known by everyone to be a relentless campaigner and likely Connecticut's next senator). Since Johnson would've lost even in a neutral year, I don't think we can blame the wave. I put most of the blame on her, while giving some credit to Murphy.
IN-2: Run a Growther against a pro-life Blue Dog in a slightly GOP district in a wave year and the Dem will win. Run them in a neutral year and, if it's Joe Donnelly and Chris Chocola, the Dem will still win. Chocola was one of the few 2006 incumbents who just lost anyway.
IN-8: Run anyone against John Hostettler in a Dem wave and Hostettler goes down. Run Brad Ellsworth and he goes down by Blanche Lincoln-esque margins. Even in a neutral year, he would've won by nearly 18 points, a horrendous showing for any incumbent without a clear scandal. But Hostettler is just that bad.
NH-2: Charlie Bass likes to play moderate, but he only is on the environment (and abortion, I believe). In 2006, voters saw through this and elected Paul Hodes, who we saw in 2010 is a very poor candidate. So do we blame the incumbent or the challenger? I actually think waves just hit NH really hard, and we could chalk this loss up to the Dem wave anyways.
NC-11: This is another reason I think Heath Shuler has been underrated. Only a single digit amount of people deserved to unseat incumbent Republicans in 2006. Except for Hodes, the others are all considered strong candidates. For some reason, Shuler isn't. He can be an ass, but Charles Taylor had been around for 16 years. Ellsworth and Shuler are also the only two to deserve to unseat representatives in Republican districts.
PA-6: Other candidates with, ahem, personal issues like Don Sherwood and John Sweeney who ran in 2006 would've survived without a wave. Curt Weldon wouldn't have. Despite what many say, Joe Sestak IS a strong candidate. Beating a corrupt institution in a district with a strong history of voting for the other party is difficult. Nancy Pelosi wasn't in the House when Weldon was elected.
TX-23: This is a special case because the district was redrawn prior to the election, but Ciro Rodriguez did unseat Henry Bonilla by a healthy margin.
Democratic Incumbents Who Should've Lost:
GA-8: Jim Marshall squeaked out a win over Former Rep. Mac Collins in South Georgia. In any other year (except 2008), Collins would've won. Ironically, Marshall would've won in a neutral year in 2010 despite the hard red turn of his district. Collins is apparently a much better candidate than Scott (or Marshall got caught napping and nearly lost in 2006).
GA-12: South Georgia was not a good place to be a Democrat, even in 2006. Freshman Blue Dog John Barrow was nearly unseated by Max Burns, whom he'd beaten two years earlier. Both of these Georgians wouldn't have been in the 110th Congress except for the wave.
IA-3: Leonard Boswell managed to do worse in 2006 than in 2010. Granted, his opponent was much stronger, but still. Really? This showing is the reason I'd nearly rate his race in 2012 Lean R. Anyways, Boswell was lucky the wave existed, because otherwise we'd be worrying who'd win a Lamberti-Loebsack general.
So, without a wave, the Democrats would've picked up 13 House seats and lost 3. That sounds reasonable to me.
Senate:
Ohio: Sherrod Brown crushed Mike DeWine here, so while states like MO and MT lost their Republicans in the wave, Ohio still counts as a pickup. I still don't know what DeWine did that caused him to lose by so much, so I'm chalking this one up to Sherrod.
Pennsylvania: On the other hand, I know exactly what Rick Santorum did that caused him to lose by so much. He gets the blame for his loss.
Rhode Island: Many people blame Lincoln Chafee's loss on the blue wave. Without the wave, he would've lost by 0.6, but a loss is a loss. Rhode Island just refused to elect a Republican, no matter how moderate (or even slightly liberal in Chafee's case).
So we have 3 Dem Senate pickups. 2006 was notable in that Democrats didn't pick up any open Senate seats despite picking up so many seats overall.
Governors:
Open Seats:
Arkansas: Mike Beebe cruised to victory in Arkansas. National Democratic waves also aren't that helpful in Arkansas.
Colorado: Bill Ritter cruised by an even bigger margin. I don't understand why his numbers tanked so badly; he was a very strong candidate (or Beauprez was really weak) in 2006.
Maryland: The 2002 red wave, and not KKT, sealed Ehrlich's election. In 2006, therefore, he lost by more than the wave, but only by about 0.1% more. That's what incumbency does for you (or else we've been wrong about the strengths and weaknesses of KKT and Ehrlich).
Massachusetts: Mitt Romney was the only Republican who could hold this.
New York: George Pataki was the only Republican who could hold this (and Giuliani, I guess).
Ohio: The Republicans ran Kenneth Blackwell.
While six statehouses were picked up, wave aside, only one incumbent lost, and it was by a few thousand votes, wave-adjusted. Again this shows how much incumbency matters in a wave.
2008:
President:
Here, we can also see which states Obama only won due to the wave. Yes, presidential elections help cause waves, but still.
Indiana, North Carolina, Florida, Ohio, Colorado, New Hampshire, and Virginia were won in the wave.
This would've given Obama the Kerry states minus New Hampshire but plus Nevada, New Mexico, and Iowa for a VERY narrow win in the electoral college but a narrow popular vote loss.
Governor:
Open Seats:
Missouri: Anyone from Matt Blunt's party was going to lose, and Jay Nixon is a strong candidate.
Dems Who Should've Lost:
Washington: Christine Gregoire's never been very popular. The wave saved her butt here.
North Carolina: An open seat with another never-been-too-popular woman, Bev Perdue, as the Dem candidate. Same analysis: the wave saved her butt.
Senate:
Open Seat Dem Pickups:
Colorado: A liberal against a conservative in a toss-up state is a good place to find out who is the better candidate. Apparently it was Mark Udall, but not by too much.
New Mexico: Same analysis here, except Steve Pearce was a very weak candidate or Tom Udall is much stronger than his cousin.
Virginia: Mark Warner would've won this in 2010, 1994, and possibly in 1940 while opposing segregation. That's how beloved he is and how not beloved Gilmore is.
Incumbents Who Deserved to Lose:
Louisiana: Mary Landrieu got her ass saved by Bush. The Dem wave following his presidency allowed her to keep her seat in a reddening state. So for those who say Kennedy was a poor candidate: not really.
Minnesota: JK, that was for sure the wave.
Landrieu was actually the only one.
So, in a neutral year, the Democrats would've won 3 open seats and lose one incumbent. Still nothing to scoff at.
House:
Seats which should've been R pickups:
AL-5: Turncoat Parker Griffith owed his seat to Bush as well. A quickly red-trending seat in the South, when open, rarely stays Dem. It did here, but in any other year, we'd have said hello to Rep. Wayne Parker.
FL-16: Well, this was an R pickup. Mahoney wouldn't have been around without the 2006 wave anyway, though.
KS-2: See above, but replace Mahoney with Boyda.
LA-2: The fact that Bill Jefferson was nearly re-elected horrifies me.
LA-6: Cazayoux won in a special election but lost here. Unless the D wave subsided between mid-2008 and November 2008, this shows again how weird specials are. Special election winners Bill Foster and Travis Childers, however, won by more than the wave.
NH-1: Carol Shea-Porter should've lost in 2006, 2008, and 2010. That's all you need to know about why I don't support her running in 2012.
NY-24: Mike Arcuri was nearly upset by Richard Hanna in 2008. Bush saved his ass as well.
PA-11: Paul Kanjorski. Ugh. So glad he's gone.
TX-17: Chet Edwards also had Bush (a resident of this district, I believe) to thank for his survival in 2008.
WI-8: Steve Kagen is the Carol Shea-Porter of Wisconsin. Why are we suggesting he run for Senate?
Open Seat D Pickups:
AZ-1: Sydney Hay was a horrendous candidate; Kirkpatrick is a moderate; the seat is swingy. Recipe for a Dem pickup even without the wave.
IL-11: I know nothing about Marty Ozinga, but to lose by 24 to Debbie Halvorson, no juggernaut herself, says something about you. He must've really been terrible.
NM-1: Heinrich narrowly outperformed the wave in a historically GOP but Dem-trending seat. I don't think it'll ever go back, at least in the near future.
NM-2: Teague outperformed the wave by more than Heinrich in a tougher seat, yet managed to lose by more than the wave in 2010.
NY-13: Mike McMahon wasn't even challenged here.
NY-25: Dan Maffei cruised.
OH-16: Even in an R-leaning district, an open seat allowed a so-so candidate to win by quite a bit.
VA-11: This quickly Dem-trending district's open status allowed a Dem to finally pick it up.
GOP Incumbents Who Just Plain Sucked:
CO-4: Marilyn Musgrave is the Sydney Hay of Colorado. Betsy Markey, while more liberal than Kirkpatrick, easily defeated her, even without the wave. Considering Markey's election margin in 2010, I'm blaming this one on Musgrave.
FL-24: Well actually, Feeney didn't suck so much as he took money from Jack Abramoff. Anyways, he was absolutely destroyed in the 2008 election.
NC-8: Either Robin Hayes is much worse than I thought or we haven't given Larry Kissell enough credit. He outperformed one wave and survived a second. Only one person beat an incumbent in 2008 while outperforming the wave and survived 2010.
End Result:
GOP picks up 12 (6 if you don't count those who shouldn't have won in 2006)
Dems pick up 11 (8 open, 3 incumbents)
So who that is still in Congress as a sophomore outperformed the wave in 2008?
Martin Heinrich, Gerry Connolly, and Larry Kissell.
2010:
I'm sure this is the year you were waiting for. Which Dems can we blame for our huge defeats?
Senate:
Incumbents Who Sucked:
Arkansas: Answering that question with Blanche Lincoln is correct. But we already knew that one; no need to analyze here
GOP Pickups Greater Than Wave:
North Dakota: This one would've gone red in 1964.
Indiana: This is one where the wave did make a difference. First, it helped convince Evan Bayh to retire. Second, it got Dan Coats into the race. Third, funding that should've gone to this race was diverted to other states like PA or WA.
Dems Should've Had These Freshmen:
Illinois: Alexi Giannoulias. We all make a big deal about the bank thing, and I still think the other guy in the primary would've won the general. However, in a neutral year, this wouldn't have mattered.
Pennsylvania: Joe Sestak. He nearly won in a very tough year.
In a neutral year, Republicans would've picked up 3 Senate seats, all in at least mildly red states.
Governor: IN A NEUTRAL YEAR
Dem pickups:
Everything we won in 2010: Vermont, Rhode Island (Chafee's a Dem now), California, Minnesota, Connecticut, and Hawaii.
Florida: Rick Scott is the best example of Republican governor who narrowly won due to the wave.
South Carolina: Vincent Sheheen needs to challenge Nikki Haley in 2014. We can pick it up.
GOP Pickups:
The Safe Ones: Oklahoma, Tennessee, Wyoming, and Kansas
Iowa: Chet Culver was very unpopular and while it would've been close, Branstad would've won in a neutral year.
Michigan: Rick Snyder. Economic conservative, social moderate or even liberal. It wouldn't have been close even in a neutral year. He IS one tough nerd.
The One I'm Unsure About:
Pennsylvania: This would've been Coleman-Franken 2.0
Other Freshmen Republicans We'd Still Have:
Nevada: I blame Rory Reid.
Alabama: It's Alabama.
Georgia: Even Roy Barnes couldn't have kept Georgia blue.
South Dakota: Dennis Daugaard may be the most obscure governor.
End Result: GOP +6 (4 in Red States, Michigan, and Iowa)
Dem +8 (6 we won, Florida, and South Carolina)
South Carolina is the only outlier. It's PVI, candidates mattering in swingy states (Scott and Culver weak, Snyder strong), and Nikki Haley.
The House:
The Open Seats
TN-6, AR-2, TN-8, LA-3: The super red Southern ones
IN-8: The not quite super red not quite Southern one
NY-29: The not quite super red Northeastern one
KS-3: The not that red Midwestern one
PA-7, MI-1, AR-1: Without the wave, would've been Toss-Up but gone GOP
Shouldn't Have Won in 2006, Underperformed in 2010:
NH-1: I already talked about Carol Shea-Porter
WI-8: I already talked about Steve Kagen
PA-10: Chris Carney couldn't even outperform the wave against DON SHERWOOD
IN-9: Baron Hill only got his seat back in a wave
FL-22: Ron Klein was at wave level in 2008 but below in 06 and 10. This against Allen West in 2 of 3 elections. So glad he's out of politics.
AZ-5: I bought the CW that Harry Mitchell was super popular. But he was below the wave against JD Hayworth.
Shouldn't Have Won in 2008, Underperformed in 2010:
ID-1: Walt Minnick is the definition of fluke
MD-1: So is Frank Kratovil
FL-8: I'm shocked (not) that Grayson underperformed
VA-2: Glenn Nye was another 2008 victory due to Bush
PA-11: Kanjorski is one of two who was around pre-2006 on this list
TX-17: Chet Edwards is the other
OH-15: Kilroy barely won an open seat in 2008
PA-3: Dahlkemper was in with the wave, out with the wave
Freshmen Who Did Worse in 2010:
NM-2: Teague faced someone who probably had more name rec. than he did
CO-4: Markey didn't get to face Musgrave a second time
MS-1: Childers narrowly beat the wave in 08 after winning a special
OH-16: Not sure why Boccieri did so poorly
NY-20: Don't know where to put Scott Murphy. Kind of an open seat but kind of not
FL-24: Kosmas was a fluke due to Feeney's corruption
IL-11: Halvorson sucked
Red Districts That Finally Realized Their Dem Reps. Voted With Obama a majority of the time:
ND-AL: Earl Pomeroy's time came
TN-4: This was just embarrassing for Lincoln Davis
FL-2: Allen Boyd's home turf is trending rightward very strongly
OH-18: It only took this district two terms to realize it, I guess
SC-5: Spratt probably would've retired in 2012 anyways. His health is poor + redistricting
Districts Dems would've picked up in any other year:
HI-1, LA-2, DE-AL: Ok, we did pick these three up
IL-10: This was embarrassing to lose in; redistricting should rectify that
CA-3: Dan Lungren is likely a dead man walking in a re-match with Bera, if he goes that route
WA-8: Dave Reichert's lucky redistricting is upon us; DelBene is much stronger than Burner
Phil Hare:
This dude gets his own category; nobody else in a Dem district lost and did worse than the wave
THE SURVIVORS (in a non-wave year):
The Freshman Class:
Denny Heck, Julie Lassa, Mike Oliverio, Ann Kuster. These four would be in Congress without the wave and would make up like a third of the freshman class.
The Red Districts Reps Who'd Still Be There:
Gene Taylor, Bobby Bright, Jim Marshall, Tom Perriello, Rick Boucher, Ike Skelton, John Salazar, Stephanie Herseth Sandlin
The Freshmen from 2008 who won without the wave:
Dan Maffei, Ann Kirkpatrick, Bill Foster
The Freshmen from 2008 (except they only won in 2008 due to the wave):
Dina Titus, Mark Schauer, Steve Dreihaus, John Adler
The Guys from 2006 who won without the wave:
Ciro Rodriguez, Mike Arcuri
The Guys from 2006 (except they only won due to the wave):
Patrick Murphy, John Hall
The Veterans From Swingy Districts:
Charlie Wilson, Jim Oberstar, Solomon Ortiz, Joe Walsh, Bob Etheridge, Melissa Bean
Interestingly, this list overlaps with the biggest election night defeats for Democrats.
So there you go. Candidates who have overperformed waves are who Dems should want running again. Note that nothing here is PVI-adjusted.